The 20 inch MCP-PMT R&D in China

The 20 inch MCP-PMT R&D in China Sen Qian,On Behalf of the Workgroup Institute of High energy Physics, Chinese Academy of Science qians@ihep.ac.cn Oct. 25. 2016

Outline 1. The JUNO and MCP-PMT; 2. The new design of the MCP-PMT prototypes; the 4 π design; the 8 inch prototypes; the 20 inch prototypes; 3. The High PDE MCP-PMT 2015; the The performance of the 20 inch prototypes ; 4. The Special Behaviors of the MCP-PMT; the High CE; The large TTS; the aging behaviors;

1. The JUNO and MCP-PMT Guang Zhou 2.5 h drive Zhu Hai High QE 20 PMTs for JUNO: Shen Zhen Hong Kong Previous site candidate Hammamatsu PMT with SBA photocathode(2012) A new design using MCP: 4π collection(2009) Daya Bay NPP Huizhou NPP Lufeng NPP 53 km 53 km Macau Yangjiang NPP Taishan NPP 20 Hammamatzu PMT 20 MCP- PMT-IHEP Requirement:High QE 20 inch PMT;Good SPE detection capability;wide dynamic range;low radioactive background;more than 20 years lifetime;can withstand 0.4MPa Pressure;> 20000 pieces; 2009:Design; 2011:Collaboration; 2012:DayaBay result; 2013:JUNO

15k MCP-PMT (75%) Contract for JUNO Signed with NNVT on Dec.16, 2015

2.1 The new design of a large area PMT The QE of 20 PMT-R3600 The QE of SBA/UBA High QE PMTs: SBA (35%) and UBA (43%) are only available in small format (< 5" diameter?) (2011) Can we improve the Quantum Efficiency of Photocathode or Photon Detection Efficiency for the large area 20 PMT??? 20 UBA/SBA photocathode PMT from Hamamatzu? QE: 20% à 40%?? 20 New large area PMT? Quantum Efficiency > 40%? or Photon Detection Efficiency: 14% à 30%

2.2 the primary design of the MCP-PMT in 2009 High photon detection efficiency + Single photoelectron Detection + Low cost 1) Using two sets of Microchannel plates (MCPs) to replace the dynode chain 2) Using transmission photocathode (front hemisphere) and reflection photocathode (back hemisphere) ~ 4π viewing angle! 100% 100% 1.Insulated trestle table 30% 30% 2.Anode 40% 3.MCP dodule 4.Bracket of the cables 40% 30% 70% 5.Transmission Photocathode 6.Glass shell 7.Reflection Photocathode 30% 70% 8.Glass joint Transmission rate of the glass: 40% Quantum Efficiency (QE) : of Transmission Photocathode 30% ; of Reflection Photocathode 30% ; Collection Efficiency (CE) of MCP : 70%; PD = QE Trans *CE +TR Photo QE Ref *CE = 30%*70% + 40%*30%*70%= 30% Photon Detection Efficiency: 15% à 30% ; ~2 at least!

2.3 Project team and Collaborators Institute of High Energy Physics, CAS effort by Yifang Wang;

2.4 The R&D plan of MCP-PMT (schedule) Design 5 (8 ) prototype transmission 5 (8 ) prototype Transmission +reflection 20 prototype Transmission +reflection Mass production The design of the IHEP-MCP-PMT The project of Daya Bay II(JUNO) Alkali metal Low price MCP Vacuum equipment Test system Prototype SPE Photomultiplier Glass Shell PreAMP & Base

2.5 The new design of the MCP-PMT prototypes 2013; 2009: the design of the MCP-PMT; 2010~2011: 5 MCP-PMT prototype without SPE; 2012: 8 MCP-PMT prototype without SPE; 2013: 8 prototypes with normal performance; QE ~ 25%@410nm; CE ~ 60%; P/V of SPE> 2.0; 2014: 20 prototypes with normal performance; QE ~ 25%@410nm; CE ~ 60%; P/V of SPE> 2.0; 2015: 20 prototypes with HDE performance; QE ~ 26%@410nm; CE ~100%; P/V of SPE> 3.0; 2016: for the high QE improvement. the mass production prepare;

2.5.1 8 prototypes with normal performance--2013 Min:16.9% Max:27.3% Average:24.6% HV Gain P/V Rise Time Fall Time Dark rate @1E7 Gain(0.25PE) 2100V ~1E7 ~4 ~1.3ns ~8.8ns ~3kHz

2.5.2 20 prototypes with normal performance--2014 Min:12.7% Max:28.5% Average:22.2% HV Gain P/V Rise Time Fall Time Dark rate @1E7 Gain(0.25PE) 2000V ~1E7 ~3 ~1.2ns ~15ns ~50kHz

Prototypes: Successful 8 and 20 prototypes with normal performance; 20 inch sphere Prototype 20 inch ellipsoidal Prototype 8 inch sphere Prototype 8 inch ellipsoidal Prototype We could successfully produce the 8 / 20 inch MCP-PMT prototype for good SPE and QE And better for CE of the MCP; Uniformity of CE, QE, TTS, we also try to improve our design of the prototype.

3. The High PDE MCP-PMT--2015 20-inch Hamamatus PMT-Dynode Ellipsoidal Glass 20-inch IHEP-MCP-PMT-Ellipsoidal Glass

3.1 The QE of the Photocathode 20 inch Prototype R12860 MCP-PMT QE@410nm ~30% ~26% Hamamatsu R12860 MCP-PMT

3.2 Waveform of the Prototype Rise Time Fall Time R12860 ~6.7ns ~17.7ns MCP-PMT ~2.2ns ~10.2ns Hamamatsu R12860 MCP-PMT

3.3. The SPE of the Prototype; HV Gain P/V R12860 1650V ~1.1E7 ~3.7 MCP-PMT 1930V ~9.6E6 ~5.6 Hamamatsu R12860 MCP-PMT

3.4. The TTS of the Prototype; HV Gain TTS @ top center R12860 1650V ~1.1E7 ~2.8ns MCP-PMT 1930V ~9.6E6 ~12ns Hamamatsu R12860 MCP-PMT

3.5. The Dark count of the Prototype; HV Gain Dark rate @ 0.25PE R12860 1650V ~1.1E7 ~25kHz MCP-PMT 1930V ~9.6E6 ~ 30kHz Hamamatsu R12860 MCP-PMT

3.6. The After Pulse Rate of the Prototype Time distribution After Pulse Rate R12860 4us, 17us 10% MCP-PMT 4.5us 2.5% Hamamatsu R12860 MCP-PMT

3.7. The Relativity Detection efficiency of the Prototype HV Gain Relativity PDE R12860 1650V ~1.1E7 100% MCP-PMT 1930V ~9.6E6 110% cut@320 cut@248 Hamamatsu R12860 MCP-PMT

3.8 The performance of the 20 inch prototypes Characteristics unit MCP-PMT(IHEP) R12860 (Hamamatsu) Electron Multiplier -- MCP Dynode Photocathode mode -- reflection+ transmission transmission Quantum Efficiency(400nm) % 26 (T), 30 (T+R) 30(T) Relativity Detection Efficiency % ~ 110% ~ 100% P/V of SPE > 3 > 3 TTS on the top point ns ~12 ~3 Rise time/ Fall time ns R~2, F~10 R~7, F~17 Anode Dark Count Hz ~30K ~30K After Pulse Time distribution us 4.5 4, 17 After Pulse Rate % 3 10 Glass -- Low-Potassium Glass HARIO-32

4.1. The Transmission + Reflection QE of the Photocathode Good situation: à Improve the total QE; à Improve the Detection Efficiency; Bad situation: à Larger Dark count; à larger TTS;

CE = 60% The p.e. into the channel directly ~60% change The Diameter of the MCP: 33mm; 50mm; The Diameter of the Hole: 6um; 8um; 10um; 12um; The Inclined Angle: 0 ; 8 ; 12 ; The Open Area Ratio: 60%;77%; The Depth of output electrode: CE = 100% The p.e. into the channel directly ~70% The p.e. from the electrod indirectly ~ 30%

MCP: Large area PC (Rrf. + Tran.) ~20cm ~8cm Relativity DE Dynode-PMT 100% MCP-PMT 110% Dynode: A mesh covering the dynode MCP: Special MCP for CE~100%

4.2 Why the TTS is large? 2 1 3 The p.e. from where? -->the Transmission Photocathode -->the Reflection Photocathode The p.e. to where? -->to the channel of MCP directly -->to the electrode and then reflect to the MCP channel indirectly The prototype The contribution to the TTS 1 The distance between the PC to the MCP; ==By adjusting the Electronic optical focusing 2 The difference between the Trans. & Ref. PC; --> with Trans. + Ref. PC for better QE; --> with special MCP for better DE; But the TTS will be worse! ==No way to adjusting; (for better QE) 3 The second electron emission part of the MCP; ==No way to adjusting; (for better DE)

4.2.2 The second electron emission part of the MCP (channel or electrode); With the contribution of the second electron from the electrode (40%), the spectrum of the TTS present several peaks, which made it s TTS worse.

4.2.3 How to improve the JUNO PMT s time resolution? optical coverage: 78% à 15,000 large PMTs (20 ) à 75% à 36,000 small PMTs (3 ) à 3% (double calorimetry + timing) R12860 (20 ) MCP-PMT(20 ) TTS @ top center ~2.8ns ~12ns 3 PMT ~1.5ns

4.3 The aging behavior of the Prototype; Dark-Box Pulse Generator NIM Crate differentiator LT-Dis VME-DAQ LED MCP-PMT Delay QDC V965 XP2020 Delay USB-V1718 Oscillograph High Voltage system SY1527 TCP/IP 2inch XP2020 (Reference PMT ) ----Monitoring the stability of the light and electronics. 20inch MCP81 (Test PMT) ----Monitoring the SPE; ----> the stability of Gain ----Monitoring the MPE (~1000p.e.) the stability of Gain ----Monitoring the pedestal; the stability of electronics;

8 MCP-PMT in 2014 with ~1000p.e. enhanced aging test, the Gain of the PMT changed to 80%@7C@1X10^7 with MPE; 20 MCP-PMT in 2016 with ~1000p.e. enhanced aging test, the Gain of the PMT changed to 90%@7C@1X10^7 with MPE; The aging behavior of the MCP better than before.

8 MCP-PMT in 2014 with ~1000p.e. enhanced aging test, the Gain of the PMT changed to 35%@14@1X10^7 with MPE; 20 MCP-PMT in 2016 with ~1000p.e. enhanced aging test, the Gain of the PMT changed to 80%@14C@1X10^7 with MPE; The aging behavior of the MCP better than before.

30 pic/ day for 2 years, 2016 HQE Production line bunch test sys Mass production 2017-2018 2014-2015 20 prototype Transmission +reflection Bunch test 2009 Design 2010-2011 5 (8 ) prototype transmission 2012-2013 5 (8 ) prototype Transmission +reflection test in NNVT: MCP-PMT only test in JUNO: MCP-PMT + Base + HV + Electronics

Thank! 谢谢! Thanks for your attention! Any comment and suggestion are welcomed!

Welcome to Kaiping

May 22-26,2017 Beijing;

TIPP2017, Beijing, May. 22-26,2017 4h, by train X-PMT workshop Nanjing, May. 27-28,2017

X-PMT workshop Dynode-PMT; MCP-PMT; Si-PMT; Gas-PMT; et.al A visit to the NNVT, who produce the MCP-PMT for JUNO.

Thank! 谢谢! If you are interesting about this workshop, please give me a e-mail.